Continuously variable automatic transmission

ABSTRACT

The continuously variable automatic transmission has a plurality of clutches and brakes wherein at least a part of the clutches is designed as wet multi-disk clutches having an inner and an outer disk carrier and wherein the inner disk carrier generally rotates and the outer disk carrier remains fixed. The clutch in which, in the operating state of stationary disengagement, the inner disk carrier remains fixed and the outer disk carrier rotates is provided with a splash-lubrication pot ( 5 ), which is situated within the inner disk carrier coaxially to the hollow shaft and which is firmly connected with a constantly rotating part ( 7 ) of the clutch, the outer wall of the splash-lubrication pot being provided with holes ( 6 ).

FIELD OF THE INVENTION

This invention relates to a continuously variable transmission for amotor vehicle having a plurality of clutches and brakes designed as wetdisk sets.

BACKGROUND OF THE INVENTION

Continuously variable transmissions for motor vehicles are widely known.EP B 434 525 thus describes an automatic transmission for motor vehicleswhich has planetary gear sets shifted by means of clutches and brakesand connected with a hydraulic torque converter provided with a lock-upclutch. This automatic transmission has one input shaft and one outputshaft with a double planetary gear set, at least one power path betweenthe input shaft and the double planetary gear set, the same as threeclutches and two brakes the selective engagement of which arranged inpairs determines different reduction ratios between the input shaft andthe output shaft. Six forward gears and one reverse gear can be obtainedby the three clutches and two brakes.

In a multiplicity of continuously variable transmissions at least theclutches are designed as wet multi-disk clutches cooled by an oil flow.The oil is mostly passed from inside to outside by the disk set, theinner disk carrier rotating during the operation in order to press theoil in radial direction through the disk set. If this is not the case,the disk set is no longer cooled over the whole lining surface.

In many transmissions there is an operating state, namely, the“stationary disengagement”, in which the outer disk carrier rotates withits disk set while the inner disk carrier remains fixed with its diskset. The cold oil centrally supplied, via the hollow shaft, therefore,is not splashed from the inside to the outside through the disk set sothat an insufficient cooling results.

The problem on which this invention is based is to configure acontinuously variable transmission with wet multi-disk clutches so thateven in the operating state of stationary disengagement with fixed innerdisk carrier and rotating outer disk carrier the disk set issufficiently cooled.

SUMMARY OF THE INVENTION

It is proposed, according to the invention, that with the clutch havingin the operating state of stationary disengagement the fixed inner diskcarrier and the rotating outer disk carrier, a splash-lubrication pot isassociated which is situated in the space surrounded by the inner diskcarrier coaxially to the hollow shaft through which the cold oil of theclutch is fed and that the splash-lubrication pot is connected with acontinuously rotating part of the clutch. The outer wall of thesplash-lubrication pot is provided with holes which allow a radial exitof the oil absorbed in direction of the disk set. The rotating partwhich is lubricated by the splash-lubrication pot is locatedconveniently to the appertaining clutch baffle plate.

The cold oil exiting through the hollow shaft is, therefore, absorbedwith the splash-lubrication pot, the collected oil being formed byrotation into a rotating oil column whereby a rotation pressure forms onthe inner side of the outer wall of the splash-lubrication pot by theholes provided in the outer wall of the splash-lubrication pot, the oilis the sprayed from the inside against the disk set so that the lattercan now be effectively cooler.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in detail below with reference to thedrawings in which an advantageous embodiment is shown. In the drawings:

FIG. 1 is a partial section through a continuously variable transmissionwith the inventive splash-lubrication pot; and

FIGS. 2a and 2 b show a section or a topview of the splash-lubricationpot.

DETAILED DESCRIPTION OF THE INVENTION

Since the expert is familiar with continuously variable automatictransmissions, only the parts essential for understanding the inventionhave been provided with reference numerals on FIG. 1. This part sectionshows that in the continuously variable transmission several wetmulti-disk clutches or brakes are provided which are marked with thenumerals 1 to 4, respectively. Clutch 1 is in an operating state ofstationary disengagement, the case in which the outer disk carrier 8belonging to the clutch A rotates with its disk set while the inner diskcarrier 9 of clutch A remains stationary with its disk set. The cold oiloriginating from the hollow shaft 10 of the transmission and fed toclutch A, in the direction of arrow f, no longer cools in this operatingcondition the disk set over its whole lining surface.

According to the invention, associated with the clutch A is now asplash-lubrication pot 5 which is situated in the space surrounded bythe inner disk carrier 9, which is firmly connected with a continuouslyrotating part, the appertaining clutch baffle plate 7 in this case, andwhich absorbs the cold oil entering in direction of arrow f. In orderthat the disk set be now cooler, the cylindrical outer wall 11 of thesplash-lubrication pot 5 is provided with a multiplicity of holes 6(FIGS. 2a and 2 b) through which the cold oil formed into a rotating oilcolumn by rotation of the splash-lubrication pot 5 is sprayed againstthe disk set in order to cool it in spite of the stationary inner diskcarrier.

Reference Numerals

1 clutch

2 clutch

3 clutch

4 brake

5 splash-lubrication pot

6 hole

7 clutch baffle plate

8 outer disk carrier

9 inner disk carrier

10 hollow shaft

11 cylindrical outer wall 11

What is claimed is:
 1. A splash-lubrication mechanism (5,7) of acontinuously variable transmission for a motor vehicle, the continuouslyvariable transmission including at least one clutch (1) and having aninner disk carrier supporting an inner wet disk set and an outer diskcarrier supporting an outer wet disk set, the clutch having an engagedstate in which both the outer disk carrier and the inner disk carrierrotate with one another and the clutch having a disengaged state inwhich the outer disk carrier rotates while the inner disk carrier isstationary so that oil does not flow from the inner disk set and to theouter disk set; the splash-lubrication mechanism (5, 7) comprising: apermanently rotating part (7) of the clutch (1), and asplash-lubrication pot (5) situated coaxially with and surrounded by theinner disk carrier and firmly connected with the permanently rotatingpart (7) of the clutch and having an outer wall having at least one holeformed therein for the passage of oil from the splash-lubrication pot(5) to the inner disk carrier, whereby centrifugal force resulting fromrotation of the splash-lubrication pot (5) with the permanently rotatingpart (7) of the clutch provides a flow of the oil from thesplash-lubrication pot (5) to the inner disk carrier through the atleast one hole formed in the splash-lubrication pot (5).
 2. Thesplash-lubrication mechanism according to claim 1, wherein thepermanently rotating part (7) of the clutch (1) is a clutch baffle plate(7).
 3. The splash-lubrication mechanism according to claim 1, wherein amultiplicity of holes are formed in the splash-lubrication pot (5) forthe passage of oil therethrough.
 4. The splash-lubrication mechanismaccording to claim 1, wherein the clutch includes a hollow shaft and theoil is fed by the hollow shaft.
 5. A splash-lubrication mechanism (5, 7)of a continuously variable transmission for a motor vehicle, thecontinuously variable transmission including at least one clutch (1) andhaving an inner disk carrier supporting an inner wet disk set and anouter disk carrier supporting an outer wet disk set, the clutch havingan engaged state in which both the outer disk carrier and the inner diskcarrier rotate and the clutch having a disengaged state in which theouter disk carrier rotates while the inner disk carrier remainsstationary; the splash-lubrication mechanism (5, 7) comprising: acontinuously rotating part (7) of the clutch (1), and asplash-lubrication pot (5) firmly connected with the continuouslyrotating part (7) of the clutch, the splash-lubrication pot (5) situatedcoaxially with and accommodated by the inner disk carrier and having anouter wall having at least one hole formed therein for the passage ofoil from the splash-lubrication pot (5) to the inner disk carrier,whereby centrifugal force resulting from continuous rotation of thesplash-lubrication pot (5), during operation of the continuouslyvariable transmission, provides a flow of the oil from thesplash-lubrication pot (5) to the inner disk carrier through the atleast one hole formed in the splash-lubrication pot (5).
 6. Thesplash-lubrication mechanism according to claim 5, wherein thecontinuously rotating part (7) of the clutch (1) is a clutch baffleplate (7).
 7. The splash-lubrication mechanism according to claim 5,wherein a multiplicity of holes are formed in the splash-lubrication pot(5) for the passage of oil therethrough.
 8. The splash-lubricationmechanism according to claim 5, wherein the clutch includes a hollowshaft and the oil is fed by the hollow shaft.